[CRYPTO] ctr: Add countersize
[linux-2.6.git] / crypto / ctr.c
index 810d5ec..b974a9f 100644 (file)
@@ -23,6 +23,7 @@ struct ctr_instance_ctx {
        struct crypto_spawn alg;
        unsigned int noncesize;
        unsigned int ivsize;
+       unsigned int countersize;
 };
 
 struct crypto_ctr_ctx {
@@ -186,7 +187,6 @@ static int crypto_ctr_crypt(struct blkcipher_desc *desc,
        unsigned long alignmask = crypto_cipher_alignmask(child);
        u8 cblk[bsize + alignmask];
        u8 *counterblk = (u8 *)ALIGN((unsigned long)cblk, alignmask + 1);
-       unsigned int countersize;
        int err;
 
        blkcipher_walk_init(&walk, dst, src, nbytes);
@@ -198,18 +198,18 @@ static int crypto_ctr_crypt(struct blkcipher_desc *desc,
        memcpy(counterblk + ictx->noncesize, walk.iv, ictx->ivsize);
 
        /* initialize counter portion of counter block */
-       countersize = bsize - ictx->noncesize - ictx->ivsize;
-       ctr_inc_quad(counterblk + (bsize - countersize), countersize);
+       ctr_inc_quad(counterblk + (bsize - ictx->countersize),
+                    ictx->countersize);
 
        while (walk.nbytes) {
                if (walk.src.virt.addr == walk.dst.virt.addr)
                        nbytes = crypto_ctr_crypt_inplace(&walk, child,
                                                          counterblk,
-                                                         countersize);
+                                                         ictx->countersize);
                else
                        nbytes = crypto_ctr_crypt_segment(&walk, child,
                                                          counterblk,
-                                                         countersize);
+                                                         ictx->countersize);
 
                err = blkcipher_walk_done(desc, &walk, nbytes);
        }
@@ -251,6 +251,7 @@ static struct crypto_instance *crypto_ctr_alloc(struct rtattr **tb)
        struct ctr_instance_ctx *ictx;
        unsigned int noncesize;
        unsigned int ivsize;
+       unsigned int countersize;
        int err;
 
        err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
@@ -270,9 +271,17 @@ static struct crypto_instance *crypto_ctr_alloc(struct rtattr **tb)
        if (err)
                goto out_put_alg;
 
-       /* verify size of nonce + iv + counter */
+       err = crypto_attr_u32(tb[4], &countersize);
+       if (err)
+               goto out_put_alg;
+
+       /* verify size of nonce + iv + counter
+        * counter must be >= 4 bytes.
+        */
        err = -EINVAL;
-       if ((noncesize + ivsize) >= alg->cra_blocksize)
+       if (((noncesize + ivsize + countersize) < alg->cra_blocksize) ||
+           ((noncesize + ivsize) > alg->cra_blocksize) ||
+           (countersize > alg->cra_blocksize) || (countersize < 4))
                goto out_put_alg;
 
        inst = kzalloc(sizeof(*inst) + sizeof(*ictx), GFP_KERNEL);
@@ -282,20 +291,21 @@ static struct crypto_instance *crypto_ctr_alloc(struct rtattr **tb)
 
        err = -ENAMETOOLONG;
        if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
-                    "ctr(%s,%u,%u)", alg->cra_name, noncesize,
-                    ivsize) >= CRYPTO_MAX_ALG_NAME) {
+                    "ctr(%s,%u,%u,%u)", alg->cra_name, noncesize,
+                    ivsize, countersize) >= CRYPTO_MAX_ALG_NAME) {
                goto err_free_inst;
        }
 
        if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
-                    "ctr(%s,%u,%u)", alg->cra_driver_name, noncesize,
-                    ivsize) >= CRYPTO_MAX_ALG_NAME) {
+                    "ctr(%s,%u,%u,%u)", alg->cra_driver_name, noncesize,
+                    ivsize, countersize) >= CRYPTO_MAX_ALG_NAME) {
                goto err_free_inst;
        }
 
        ictx = crypto_instance_ctx(inst);
        ictx->noncesize = noncesize;
        ictx->ivsize = ivsize;
+       ictx->countersize = countersize;
 
        err = crypto_init_spawn(&ictx->alg, alg, inst,
                CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_ASYNC);